Ruby Issue Tracking System

08/10/2026

11:12 PM Ruby Bug #22220 (Closed): Performance regression when requiring `aws-sdk-ec2` in Ruby 4.0.6

Applied in changeset commit:git|5c9bb97ca8bec233745af117a396430db47725f6.
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Optimize DCE
[Bug #22220]
ref: https://bugs.ruby-lang.org/issues/22220
1f473ed633 split the walk into a counting pass and a deletion pass -- but
the... viralpraxis (Iaroslav Kurbatov)

11:12 PM Ruby Revision 5c9bb97c (git): Optimize DCE

[Bug #22220]
ref: https://bugs.ruby-lang.org/issues/22220
1f473ed633 split the walk into a counting pass and a deletion pass -- but
the counting pass only stops at `leave`, so it scans to the end of the
ISEQ on every call.
`opt_new` c... viralpraxis (Iaroslav Kurbatov)

09:45 AM Ruby Bug #22126: Stack underflow for partial DCE and loops

The patch introduced a performance regression (see https://bugs.ruby-lang.org/issues/22220), I believe https://bugs.ruby-lang.org/issues/22220#note-3 should fix that. viralpraxis (Iaroslav Kurbatov)

08/03/2026

04:56 PM Ruby Bug #22220: Performance regression when requiring `aws-sdk-ec2` in Ruby 4.0.6

Possibly fixed by https://github.com/ruby/ruby/pull/18181 viralpraxis (Iaroslav Kurbatov)

07/09/2026

10:01 PM Ruby Revision e36708fa (git): [Bug #22181] Fix branch-peephole-optimization label & insn ID collisions

viralpraxis (Iaroslav Kurbatov)

07/05/2026

12:46 PM Ruby Bug #22181 (Closed): SEGV in branch peephole optimization due to label/insn struct aliasing

Applied in changeset commit:git|6aedc31694f020ee37cd0668779351a714115ad0.
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[Bug #22181] Fix branch-peephole-optimization label & insn ID collisions viralpraxis (Iaroslav Kurbatov)

10:39 AM Ruby Bug #22181 (Closed): SEGV in branch peephole optimization due to label/insn struct aliasing

Both `iseq_label_data` and `iseq_insn_data` share the same layout prefix; in some cases `iseq_label_data->label_no` might collide with `iseq_insn_data->insn_id` (e.g. when there are many (monotonically increasing) label IDs allocated and... viralpraxis (Iaroslav Kurbatov)

12:46 PM Ruby Revision 6aedc316 (git): [Bug #22181] Fix branch-peephole-optimization label & insn ID collisions

viralpraxis (Iaroslav Kurbatov)

06/26/2026

09:34 PM Ruby Revision e4c52b41 (git): [Bug #22126] Fix partial DCE with loop back-edges

The old `remove_unreachable_chunk` walked the dead code once and tried
to do two things at the same time -- count label references inside that
chunk and figure out what exactly to delete.
That breaks for loops -- the loop label comes be... viralpraxis (Iaroslav Kurbatov)

06/24/2026

03:41 AM Ruby Bug #22126 (Closed): Stack underflow for partial DCE and loops

Applied in changeset commit:git|1f473ed633a364f8c89b69a76adfb22a4bf21f96.
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[Bug #22126] Fix partial DCE with loop back-edges
The old `remove_unreachable_chunk` walked the dead code once and tried
to do two things at the same ... viralpraxis (Iaroslav Kurbatov)